I. Field of the Invention
This invention relates to a method of producing a film or membrane of a high molecular substance, and more particularly to a method of producing a membrane of a crosslinked high molecular substance suitable for use as a separation membrane.
II. Description of the Prior Art
A high molecular membrane is widely used in the medical field as a membrane adapted for living bodies or as a membrane for separating a mixture of different substances by utilizing reverse osmosis. As a high molecular substance used for such a purpose, particularly excellent is a block copolymer consisting of a hydrophilic monomer block unit and a hydrophobic monomer block unit. In such a block copolymer, the chain length of each block and the ratio of the hydrophilic monomer unit to the hydrophobic monomer unit are very important for enabling the copolymer to be suitable for use for the above-noted purpose.
It is conventional to produce a block copolymer by utilizing a graft polymerization reaction or a block polymerization reaction. In the conventional method, however, it is necessary to use an initiator or a chain transfer agent for carrying out the required polymerization reaction, resulting in restriction in terms of the control of the molecular chain length and of the block unit ratio.